Few want to even think about it, but the 2012 US election result could be clouded by problems with voting machines ... again.

Twelve years after the Florida punch card debacle in which thousands of votes went uncounted in the crucial state, some experts cite similar concerns about voting technology.

"I'm not sure we've made forward progress since 2000," said Douglas Jones, a University of Iowa computer scientist and co-author of a book published this year, "Broken Ballots."

"We've put a tremendous effort into changing the voting systems, but in many cases we've discarded systems too quickly and replaced them with systems that we haven't examined enough."

Jones said technology used on some vote machines is now close to a decade old and should be updated. And some systems have security flaws or may not allow for recounts or audits, he noted.

"Whenever an election is close all of the weaknesses become apparent," he said. "I expect there will be some states where the margin is so close that people will raise questions about irregularities."

A frequent target for critics is the use of touchscreen voting machines, which lack a paper backup. Around 25 percent of Americans are expected to use paperless electronic voting, according to the Verified Voting Foundation.

A report earlier this year by two activist groups and the Rutgers University School of Law said systems used in 20 states were either "inadequate" or needed improvement.

That includes 16 states which use paperless machines in some or all jurisdictions. Six states were ranked "good" and 24 "generally good."

-- Storm becomes wild card --

Hurricane Sandy's destruction has added another element of uncertainty, says Thad Hall, a University of Utah political scientist and researcher for the Voting Technology Project.

"No power means that (vote machines) will only operate as long as their batteries last," he said. "It also means that voters voting on paper ballots will not have the use of scanners to identify errors on their ballots."

The devastation also means "some voters will literally not be able to vote because they will have been evacuated from their local polling place and there is no provision for remote voting."

Hall said the storm probably had a disproportionate impact on supporters of President Barack Obama, creating new political risks even if the incumbent carries those northeast states.

Lower turnout "may not mean that Obama does not win the affected states but it could mean that we have a re-run of 2000 -- an electoral college winner who does not win the popular vote," he said.

A report last month by the Voting Technology Project, a joint effort by the California Institute of Technology and Massachusetts Institute of Technology, found some electronic voting systems had a failure rate as high as punch cards.

-- Technology: solution or problem? --

The report said between four million and six million votes were "lost" in the 2000 election, and that despite some progress since then, it's not clear whether the problems could be repeated.

"What has changed since 2000? In many respects, there have been profound changes in the voting equipment business, but in some very important respects, very little about this business has changed," the report said.

The report said growth in mail-in and early voting raises new questions and Internet voting available to overseas or military voters raises security issues.

Charles Stewart, an MIT professor and member of the project, said the most likely problems may come from mail-in paper ballots, which have increased as states ease absentee restrictions.

He said these are problematic because "absentee ballots are not secret ballots, they generally don't have a secure chain of custody, and they are prone to be disputed."

Jones meanwhile is among computer specialists who argue that paper ballots scanned by computers remain the most reliable method.

"Everything is complicated if you have no paper backup," he said. "If the scanners fail you can hand count the paper ballots. If touchscreens fail, what can you do?"

But Paul DeGregorio, a former chairman of the US Election Assistance Commission and currently a consultant, says technology should be seen as the solution, not the problem.

"Of course there are the naysayers to progress and change. They believe paper and pencil is the answer to everything; that technology is not our friend -- and that it cannot be trusted, under any circumstance," DeGregorio said in a commentary to the CalTech/MIT report.

He added that "modern technology can make it easier to confirm legitimate voters and also catch those who are trying to vote illegally," and that electronic systems have "prevented thousands of voter errors."